White-handed Gibbon

Range:

Indo-China and Thailand, west of Mekong River, Tenasserim; Malay Peninsula and Sumatra.

Habitat:

Tropical rain forests from sea level to about 6,500 feet elevation.

Characteristics:

Small tailless apes with very dense, silky, shaggy fur varying from black or dark brown to pale fawn or silver grey. Slender body with short and broad chest cavity. Round head is small with flat forehead and developed chin; brain is relatively small. Framed by white fringe, face is bare and deeply pigmented. Snout is not protruding; nostrils are more widely spaced and more lateral than Old World Monkeys. Small jaws with long canine teeth. Arms are greatly elongated, legs and feet less so. Upper sides of hand and feet are always white ('white-handed'), contrast is less apparent in the buff specimens. Prehensile hand with small opposable thumb. Thumb is not used during brachiation, but for climbing tree trunks and thick branches, for manipulation of food and grooming. Males and females look alike.

Behavior:

Active during the day (diurnal). Prefer closed canopy but during feeding may climb to highest emergent crowns of trees or descend to clumps of bamboo and low bushes, or to drink. When drinking, they hang from overhanging branches and quickly dip hands into the water. Probably fastest of all primates; most agile of all mammals in trees. Swing from branch to branch (horizontally or vertically), with legs flexed under body; using arms alternately and keeping hand bent in hook shape, movements appear effortless. Can swing so far forward they "fly" up to 40 feet through air and leap downward about 50 feet, until they hook another limb or land on their feet on a solid perch. Often cross wide gaps in forest or over rivers in this manner. Able to change direction even during fastest bounding by slightly touching a branch. While swinging, able to catch birds out of the air and eat them after landing. Accidents are a fairly common occurrence in the wild. If a branch breaks, even acrobatic agility will not save it. Fractured limbs are commonly found in wild shot specimens. Brachiation constitutes 90% of arboreal locomotion. Other patterns include climbing, bipedal walking on branches, with or without support of arms. When walking or running on ground, arms are held high for balance and they move in a waving manner. They usually associate in family groups consisting of male, female, and several offspring of various ages; following a strict daily routine. Male dominance does not exist within the group. Playful 'biting' matches, which can be painful to a human, seem to determine rank order of mature juveniles within the group. Even serious bites don't seem to hurt them because of their dense fur. In friendly greetings, corners of mouth are drawn back, revealing teeth, and tongue is sometimes protruding. In anger, mouth is opened and closed repeatedly, smacking lips and snapping teeth together. Snarling is interpreted as an intention of biting. Each family defends its territory by song and threat display. They do not construct sleeping nests but show preference for specific 'sleeping trees' where no other family group is tolerated. They sleep sitting erect in trees, huddled together in twos and threes, with knees bent up to chin, hands folded on knees and face buried between the knees and chest.

Reproduction:

Gibbons are self-willed 'personalities' in their mating preferences; not very easily bred in captivity. One young born is after a gestation period of 200-212 days, usually at two-year intervals. Eyes are open at birth and body and limbs are bare; very dependent on their mother for warmth. Many are white at birth and do not become black or final color until 2-4 years old. Sexual maturity occurs at about 8-10 years.

Interesting Facts:

Their loud resonant songs can be heard up to 1/2 mile away. Songs by far excel those of most other species because of a sound-amplifying throat sac. Most often hear in early morning and again in the evening hours. The male and female usually sing different parts of a duet, complimenting each other.

About Our Animals:

We have a pair of Lar gibbons. The female, Candy, was born in Jackson Zoological Park in May 1982 and has been at the Hogle Zoo since 1988. Our male, Riley, was born in Santa Barbara Zoo in August 2000 and came to Hogle Zoo in May 2009. Their introduction to each other went very smooth and they are starting to build a strong bond. The Gibbon SSP has recommended that we breed this pair, so we are hoping that they produce an offspring in the future.

Leopards, clouded leopards, man. Thanks to keen sense, agility, and adaptability, man's progressive settling of their habitat has not caused them as extensive damage as is experienced by the great apes.